Valve for rock drills



Dec. 10, 1929. HULSHlZER 1,739,143

VALVE FOR ROCK DRILLS Original Filed July 19, 1927 12 I 5 LH r fl H Gear ew iz f i z jezr 1 Doc. to, 1929 STATES PATENT O C GEORGE W. HULSHIZEB, OF BTEWABTSVILLEJIEW JERSEY, ASSIGNOB TO INGERSOLL- RAND comm, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEWJERSEY VALVE FOB ROCK DRILLS Application filed July 19', 1927, Serial No. 206,848. Renewed April 4, 1929.

This invention relates to rock drills, but more particularly to a distributing valve for fluid actuated rock drills of the hammer type.

The objects of the invention are to. obtain 5 a durable valve of light weight, to effect a rapid distribution of pressure fluid to the cylinder and to prevent fluttering of the valve in its limiting positions.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings illustrating a practicalembodiment of the invention,

.Figure 1 is a longitudinal sectional elevation of a portiorrof a rock drill showing the valve in position'to'admit pressure fluid to the rear ward end of the cylinder, and

Fi ure 2 is a view similar to Figure 1 showingitlie valve in its other limiting position.

eferring to the drawings, the invention is shown embodied in a rock drill having a cylinder A closed at its front end by a bushing B and at its rearward end by aback head C. In the cylinder A is disposed a reciprocator hammer piston D which controls a free exhaust port E in thecylinder and has a forwardly extending reduced shank F slidable in v the bushing B. 1

On the side' of the cylinder A is a valve chest G having an annular bore H which exa point near the front end thereof, thus forming an end'wall J at the front end of the chest G.

At the open end of the bore H is formed a bushing 0 having in this instance a passage P which communicates with a passage Q in the back head C. tle valve R of any suitable type is interposed in the passage to control communication between the passa e P and a source of pressure fluid supply not shown).

In thefront end of the bore H is disposed a bushing S which abuts the wall J and has a wall J to receive a nut whereby the bushingS is secured firmly in position. The bushings O and S are provided with bores V which form the smaller portions of a valve chamber W. In the present instance the bushings 0 sages .Y. The rearward and front ended and 6 retends from the rearward end of the chest toan annular recess K to receive aflange L of- Preferably, a throtthreaded extension T prtgjecting through the and S are suitably spaced withrespect to each other to form an enlarged portion X of the valve chamber W between the inner ends of the bushings.

Pressure fluid for actuating the piston D is convleyed to the cylinder through inlet pas- I and Z leading from the front and rearward ends respectively of the valve chamber W to the corresponding ends of the cylinder A.

Disposed in the valve chamber W is a distributing valve 6 having in this instance a bore 0 therethrough for conveying pressure fluid from the passage P to the inlet passage spectively of the valve are preferably so formed as to enable them to lie flush against adjacent ends f and g of the bushings O and S. The ends at and e when out of contact with the respective faces which they are intended to abut serve as holding faces against which pressure fluid may act for holding the valve in its extreme positions. For instance, with the valve in the position illustrated in Figure 1 the end face (i is exposed to live pressure fluid flowing into the inlet passage Z and the face 6 is thus held firmly against the face 9 of the bushing S.

Intermediate the ends of the valve is formed an enlarged flange h which reciprocates in the enlarged portion X of the valve chamber. The flange h divides the enlarged portion X into forward and rearward pressure chambers j and is into which pressure fluid is intermittently admitted from the interior of the valve by leak ports 0 and p in the valve registering with passages and 1' respectively leading from the bores to the enlarged portion W. The pressure fluid admitted into the pressure chambers y and la acts against forward and rearward actuatin and holding surfaces 8 and t of the flange for actuatingthe valve, as Well as to assist in holding the valve after it has been thrown. In the construction shown, the bushing O is provided with a passage u which leads from the inlet passage Z to the pressure chamber k for exhausting pressure fluid from said pressure chamber into said inlet passage Z upon an occurrence of a drop in pressure in 100 the rearward end of the cylinder. Similarly, a passage '0 is formed in the bushing S to establish communication between the pres- The operation of the device is as follows:

with the valve in the position illustrated in Figure 1, pressure fluid will pass over the rearward end d of the valve and through the inlet assage Z into the rearward end of the cylin er to impel the piston D forwardly. During the admission 0 pressurefluid to the rearward endof the cylinder, the valve b is held'immovable in the front end of the valve chamber W b the pressure fluid acting against the en surface (Z of the valve and against the surface t of the flange h. During the admission of pressure fluid to the rearward end, however, a portion of the pressure fluid will flow through the port-0 and the passage q into the pressure chamber to act against the surface s of the flange h. (lwing to the fact, however,.that the front end surface 0 of the valve lies flush against the surface 9 of the bushing S, the pressure fluid acting againstthe rearward end surfaces of the valve will redominate over that acting against the sur ace 8 and the valve will thus remain in its forward position until the piston D opens the exhaust port E. Opening of the-exhaust port will cause a drop in pressure in the rearward end of the cylinder and consequently on the surfaces d and't and the pressure fluid in the ressure chamber 7' will immediately cause t e valve 6 to start in a rearwardly direction. After the contact between the surface e and g has been broken, the front end surface e will also be exposed to live pressure fluid to assist in throwing the valve rearwardly.

- Upon reversal of the valve b, pressure fluid will flow over the front end of the valve and through the inlet passage Y to the front end of the cylinder and impel the piston D rearwardl At the same time, pressure fluid will flow t rough the port and the passage 1' into the pressure chamber preparatory to throwing the valve forwardly. Duringthe admission of pressure fluid to the front end of the cylinder, the valve is held in its rearwardmost position by pressure fluid acting on the surfaces 8 and e and will; remain in this position until the piston uncovers the exhaust port during its rearward stroke, thereby causing a sufilcient dro in pressure forwardly of the surfaces 6 an e to enable the pressure fluid in the chamber'k to again throw the valve forwardl to its initial position.

As be observed, the ports 0 and p are chamber to the ends of of considerably smaller cross sectional area than the passages u and 'v, and therefore a slightly greater period of time is required to admit. pressure fluid into the pressure chambers j and is than to exhaust the pressure fluid from these chambers. It is this difierential in area between the ports 0 and and the passages u and 'v which enables t e valve to remain immovable in its extreme positions until the piston D has traveled to the ends of the cylinder.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and piston, a valve chest having a valve chamber, inlet passages leading from the valve chamber to thecylinder, a distributing valve in the valve chamber having a bore for conveying pressure fluid therethrough, the ends of said valve cooperating with the ends of the valve chamber 1 for controlling the admission of pressure fluid into the cylinder, a flange on the valve intermittently havin actuating and holding surfaces, ports in t 'e valve conveying pressure fluid into the valve chamber to act against the said surfaces, and passages in the valve chest forexhausting such pressure fluid into the inlet passage upon an occurrence of a drop in pressure in the ends of the cylinder. 2. In a fluid actuated rock drill, the combination of a cylinder and piston, a valve chest having a valve chamber with an enlarged portion, inlet passages leading from the valve the cylinder, a valve in the valve chamber having a bore therethrough constantly exposed to live pressure fluid, the ends of said valve cooperating with the ends of the valve chamber for controlling the admission ofpressure fluid into the cylinder, a flange on the valve dividing the enlarged portion into pressure chambers, the ends of said flange constituting actuating and holding surfaces, ports in the valve intermittently admitting pressure fluid into the pressure chambers to act against said surfaces, and passages in the valve chest exhausting pressure fluid from the pressure chambers into the inlet passages upon the occurrence of a drop in pressure in the ends of the cylinder.

3. In a fluid actuated rock drill, the combination of a cylinder and piston, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, said valve chamber comprising an enlarged centraLportion and smaller end portions, a distributing valve in the valve chamber having a bore therethrough constantly communicating with a pressure fluid supply, the ends of said valve coo crating with the ends of the valve chamber orcontrolling the admission of pressure fluid into the cylinder, a flange on the valve dividing the enlarged portion into a pair of pressure. chambers, passages leading from the enlarged portion to the smaller portions of the valve chamber,

ports in the valve intermittently re 'stering with said passages to admit pressure uid into the pressure chambers for actuating and holding the valve, and passages in the valve- 5 chest of larger cross sectional area than the ports for exhausting pressure fluid from the pressure chambers into the inlet passages upon the occurrence of .a drop in pressure in the ends" of the cylinder.

10 In testimony whereof I have signed this specification.

GEORGE W. HULSHIZER. 

